ares_getaddrinfo() of port 0 reports ARES_ESERVICE

[bagder]

... while using glibc's getaddrinfo() with the same port number works fine.

(I use ARES_AI_NUMERICSERV set in ai_flags)

Is there actually any good reason to refuse just using 0 as a dummy port?

[bradh352]

When you say zero, are you passing 0 (aka NULL) as the "service" argument, or are you passing the string "0"?

[bagder]

The string "0", like this:

https://github.com/curl/curl/blob/a51f90ec0f74176776f5d14b99689f9241660eaa/lib/asyn-ares.c#L784

I modified the code to instead use the string "80" as a work-around, and then it succeeds (with both glibc and c-ares).

[bradh352]

Interesting use case. Typically if you don't care about the service port in a dns lookup, you'll just pass NULL to that field. But if other implementations support this, we definitely can too, its a trivial change.